Demoulding apparatus

ABSTRACT

For use in manufacturing concreted building products in polyurethane molds, a demolding apparatus provides a clamping bar which clamps on to a lip of a mold (22) and is then moved with pivotal arms (32,34) forward and upwardly to effectively strip the edge of the mold (22) form the front end of the respective product (24). The reciprocating mold (22) passes below a roller (66) which moves into engagement with the upper surface of the mold (22) to apply a downwardly directed pressure onto the mold and product, thereby to retain the product (24) on a conveyor (12) and rollers (68), and facilitate stripping of the mold (22) from the product (24). The stripped product (24) moves onto an offtake conveyor (70) and, in the uppermost position of the arm (32,34), the clamping jaws are released to allow the stripped mold (22) to thereafter fall onto the conveyor (70).

This application is a national stage application, according to ChapterII of the Patent Cooperation Treaty. This application claims thepriority date of Oct. 23, 1993, for UK Patent Application No. 9321923.6.

This invention relates to demoulding apparatus, particularly apparatusfor automatically removing flexible moulds from moulded components suchas concrete building products.

At the present time, flexible moulds, such as polyurethane moulds, areusually manually stripped from moulded concrete building products. Thishas several disadvantages, not the least of which is that the demouldingis very labour intensive. In GB1498833, an open-topped flexible mouldwith a moulded component therein is moved along a belt conveyor. At theposition of a drum roller at the end of the conveyor, edges of the mouldengage with abutment members which cause the mould to move around thedrum roller but enable the moulded component to continue on a linearpath away from the mould. Such an arrangement has limited use, forexample only for shallow moulds.

According to the present invention there is provided demouldingapparatus comprising means for supporting a mould with a mouldedcomponent therein, characterised by means for releasably gripping themould, and means for moving the gripping means in such a direction awayfrom the support means that a mould formed of a flexible material, whengripped at one edge by the gripping means, can be stripped from said oneedge of the component to an opposed edge thereof, whereby to remove themould from the component.

Preferably the apparatus includes means for retaining the mouldedcomponent on the supporting means while the mould is stripped from thecomponent.

Preferably also the supporting means includes a conveyor for moving themould with the component therein in a linear path to an operativelocation of the gripping means. The supporting means may further includemeans over which the component can continue to move in the linear pathas the mould is separated therefrom.

The gripping means may include a clamp which is movable between aninoperative position and an operative position wherein the clamp gripssaid one edge of the mould. The clamp may be supported by an armarrangement which is movable through an angle. The clamp may compriseclamping jaws, the movement of which is pneumatically controlled,preferably by a pair of spaced pneumatic piston and cylinder assembliestowards respective ends thereof.

The retaining means may be movable between an inoperative position andan operative position wherein the retaining means engages the mould withthe component therein in a spaced relation to said one edge, whereby toenable stripping as the component continues to move along the linearpath. The retaining means may be in the form of a freely rotatableroller, or in the form of a trolley with freely rotatable wheels, whichmay be controlled by a pneumatic piston and cylinder assembly.

The apparatus may be associated with a further conveyor, one end ofwhich is located adjacent to a loading position, and the other end ofwhich is located adjacent to means for moving the demoulded componentand the empty mould, whereby a mould supporting member can be removedfrom the mould before loading the latter, and the mould supportingmember can be moved by the further conveyor from said one end thereof tothe other where the mould support member can be reunited with an emptymould. The apparatus may be adapted to strip a plurality of moulds fromrespective components simultaneously.

The invention also provides a demoulding method comprising the steps ofsupporting a flexible mould with a moulded component therein, andcharacterised by gripping one edge of the mould, and moving the mould ina direction away from the supporting means, whereby to strip the mouldfrom said one edge of the component to an opposed edge thereof, wherebyto remove the mould from the component.

Preferably the method includes the step of retaining the component onthe supporting means while the mould is stripped from the component. Themould may be moved through an angle away from the component.

Preferably the mould with the component therein is moved in a linearpath to an operative location whereat the mould is clamped and movedaway from the supporting means, the component continuing to move in thelinear path to enable stripping of the mould from the component.Pressure may be applied to the mould with the component therein at aspaced location from said one edge of the mould, whereby to retain thecomponent on the supporting means while separation takes place.

An embodiment of the present invention will now be referred by way ofexample only, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side elevation of an apparatus according to theinvention;

FIG. 2 is an end elevation;

FIG. 3 is a schematic plan of a demoulding line incorporating anapparatus of the invention; and

FIG. 4 shows a modification of part of the apparatus.

Referring to the drawings, FIG. 3 shows a twin lane demoulding lineincorporating a demoulding apparatus 10 into which products aredelivered by a twin lane roller chain conveyor 12 from an operator feedstation 14. Concrete building products are often produced in singlecavity or multicavity polyurethane moulds supported in wooden trays,which are transported to the feed station 14 on pallets by a forklifttruck. Operators at the feed station 14 lift each tray with the mouldand the moulded product from the pallet and, by upturning the tray, loadthe mould with the product upside down on to the conveyor 12. Gravityroller conveyors 16, 18 are located on respective sides of the conveyor12, the conveyor 16 being provided with a lift gate 20 to enableoperator access to the demoulding apparatus 10. The operator places anempty tray onto the adjacent one of the conveyors 16, 18, the empty traythen travelling to the other end of the respective conveyor for apurpose hereinafter described.

Pairs of upturned moulds 22 (see FIG. 1) with the respective mouldedproducts 24 are delivered into the apparatus 10 by the conveyor 12. Eachof the moulds 22 is formed with an outwardly extending peripheral lipwhich, when the mould is upturned on the conveyor 12, rests on thelatter. The apparatus 10 has frame members which mount demouldingcomponents as hereinafter described, with wire mesh extending betweenthe respective frame members for operator protection. Extendinglaterally of the apparatus 10 between opposite vertical frame members26, 28 (FIG. 2) is a rotatable drive shaft 30, on respective ends ofwhich are mounted first ends of a pair of arms 32, 34 which arerotatable with the shaft 32 for a purpose hereinafter described. In amodification, the axis of rotation of the arms 32, 34 may be adjustable.Each arm 32, 34 mounts, on an inner face, respective mounting lugs 36,38 for a respective cylinder 40, 42 of a piston cylinder assembly. Eachpiston 44, 46 extends from the associated cylinder and mounts on itsfree end a respective leg of a laterally extending clamping bar 48 whichhas closable clamping jaws. A pair of detection pads 50 are provided onthe clamping bar 48 at locations engageable by each pair of moulds 22.

The arms 32, 34 are normally retained in a position extending verticallydownwardly of the drive shaft 30, as shown in full lines in FIG. 1,whereby the clamping bar 48 with the pads 50 are in the path of movementof the moulds 22 on the conveyor 12. This position of the arms 32, 34 ischecked by a microswitch 52 engaged by a bracket 54 externally of thearm 32. The leading edges of the peripheral lips of the moulds 22, asthe latter move off the end of the conveyor 12, as shown in FIG. 1,locate between the jaws of the clamping bar 48. When the moulds 22engage the pads 50, this operates a microswitch which in turn operatesthe piston and cylinder assemblies of the clamping bar 48, whereby thepistons 44, 46 are retracted, to close the clamping jaws and clamp thelips of the moulds 22.

A further microswitch on the clamping bar 48 is operated by engagementof the latter with the moulds 22 and energises a motor which rotates thedrive shaft 30 and thereby moves the arms 32, 34 forwardly and upwardlythrough a required angle while the clamping bar 48 grips the lips of themoulds 22.

On a transverse frame member 56 of the apparatus 10, a further pistonand cylinder assembly extends downwardly towards the conveyor 12. Thecylinder 58 thereof is fixed to the frame member 56 and the free of thepiston is connected centrally of a transverse bar 60, each end of whichis connected to a free end of a respective one of a pair of longitudinalbars 61. The other ends of the latter are pivotally mounted on theframework. Further bars 62 are adjustably mounted on respective ones ofthe bars 61 by means of mounting plates 64. At their free ends the bars61 mount therebetween a freely rotatable transverse roller 66.

Extension of the piston out of the cylinder 58 effectively pivots theroller 66 downwardly through an arc. The roller 66 in its normalposition locates above a series of free rollers 68 which locate in aspace between the inner end of the conveyor 12 and the inner end of aroller chain offtake conveyor 70.

In a modification, as shown in FIG. 4, the bars 62 are replaced by arestraining arm 80 which, at its free end, pivotally mounts a trolley 82in the form of a pair of spaced triangular plates 84 between which aremounted a pair of spaced freely rotatable rollers 86.

The arms 32,34 for mounting the clamping bar 48, in this modificationare each profiled to have an angled section 88, whereby to locate theclamping bar 48 in a position forwardly of the restraining trolley 82,which can therefore be moved to an operative position prior tocommencement of the mould stripping.

In a further modification, a conveyor or other movable support may beprovided as an alternative to the three rollers 68.

In operation, after the jaws of the clamping bar 48 clamp on to the lipsof the moulds 22, and the bar 48 moved with the arms 32, 34 forwardlyand upwardly, the edges of the moulds 22 are effectively stripped fromthe front ends of the respective products 24. The separating moulds 22pass below the roller 66 which is then moved downwardly into engagementwith the upper surfaces of the moulds 22 to apply a downwardly directedpressure on to the moulds and products, thereby to retain the products24 on the conveyor 12 and the rollers 68, and facilitate stripping ofthe moulds 22 from the products 24. The action is to effectively peelthe moulds 22 from the products 24 and pull the products 24 through theapparatus and onto the offtake conveyor 70.

When the arms 32, 34 reach the end of the angular travel (as shown inchain dotted lines in FIG. 1), the moulds 22 have totally separated fromthe components 24 which have moved onto the offtake conveyor 70. In theuppermost position of the arms 32, 34, a microswitch operates to releasethe clamping jaws whereby the moulds 22 are allowed to fall onto theofftake conveyor 70. The demoulded products 24 are therefore followed onthe conveyor 70 by the empty moulds 22. The arms 32, 34 are thenreturned from their uppermost position to their start position, in orderto receive further moulds with products.

In the modification of FIG. 4, the empty moulds may alternatively bedeposited on a gravity roller conveyor 90.

The demoulded products 24 then arrive at a collating station 72 fromwhere the demoulded products travel through to a packing station 74 forappropriate handling by operators. The gravity roller conveyors 16, 18terminate at the collating station 72, where operators can reunite theempty moulds from the conveyor 70 onto empty wooden trays from theconveyors 16, 18, for transport to a moulding location.

It should be appreciated that the load and unloading operations could becarried out automatically by suitable apparatus. Also, instead of beingsupported in wooden trays, a plurality of moulds may be supportedtogether in a large housing from which the moulds with the products canbe simultaneously released and loaded onto the conveyor.

Further, although the described embodiment utilises a twin lanedemoulding line, the demoulding line may have more than two lanes, forexample up to eight or nine lanes. Because certain dimensions of a rangeof moulds would remain the same, and because each of the range of mouldsis formed with the same peripheral lip, the apparatus can handle mouldswhose other dimensions can vary, and can handle such different sizes ofmoulds simultaneously, whereby the apparatus is very versatile.

There is thus provided a demoulding apparatus which can automaticallystrip or peel a flexible mould from a concrete product, therebyobviating or mitigating the disadvantages associated with the manualoperations. Also, the whole operation is enhanced by the provision forautomatically moving empty trays and empty moulds through desiredlocations to minimise manual handling.

Various modifications may be made without departing from the invention.For example the configuration of the various components may differ fromthat described and shown, and the invention is not limited to themoulding of concrete building products in flexible polyurethane moulds.

We claim:
 1. Demoulding apparatus comprising means (12) for supporting amould (22) which has an open side and a moulded component (24) therein,characterized in that, for use in demoulding when the mould is supportedwith the open side facing the supporting means (12), there is providedmovable gripping means (48) for releasably gripping the mould (22), andmeans (32, 34) for moving the gripping means (48) in such a directionaway from the support means (12) that a mould (22) formed of a flexiblematerial, when gripped by the gripping means (48), can be stripped fromone edge of the component (24) to an opposed edge thereof, whereby toremove the mould (22) from the component (24).
 2. Apparatus according toclaim 1, characterized by means (60-66) for retaining the mouldedcomponent on the supporting means (12) while the mould (22) is strippedfrom the component (24).
 3. Apparatus according to claim 1,characterized in that the supporting means (12) includes a conveyor formoving the mould with the component therein in a linear path to anoperative location of the gripping means (48).
 4. Apparatus according toclaim 3, characterized in that the supporting means further includesmeans (68) over which the component (24), after leaving the conveyor cancontinue to move in the linear path as the mould (22) is separatedtherefrom.
 5. Apparatus according to claim 1, characterized in that thegripping means (48) includes a clamp which is movable between aninoperative position and an operative position wherein the clamp gripsone edge of the mould (22).
 6. Apparatus according to claim 5,characterized in that the clamp is supported by an arm arrangement (32,34) which is movable through an angle.
 7. Apparatus according to claim5, characterized in that the clamp comprises clamping jaws, the movementof which is pneumatically controlled.
 8. Apparatus according to claim 7,characterized in that movement of the clamping jaws is controlled by apair of spaced pneumatic piston and cylinder assemblies (40-46) towardsrespective ends thereof.
 9. Apparatus according to claim 5,characterized in that the retaining means (60-66) is movable between aninoperative position and an operative position wherein the retainingmeans (60-66) engages the mould (22) with the component (24) therein ina spaced relation to said one edge, whereby to enable stripping as thecomponent (24) continues to move along a linear path.
 10. Apparatusaccording to claim 9, characterized in that the retaining means is inthe form of a freely rotatable roller (66).
 11. Apparatus according toclaim 9, characterized in that the retaining means is in the form of atrolley with freely rotatable wheels.
 12. Apparatus according to claim10, characterized in that movement of the retaining means is controlledby a pneumatic piston and cylinder assembly (58).
 13. Apparatusaccording to claim 1, characterized in that the apparatus is associatedwith a further conveyor (16, 18), one end of which is located adjacentto a loading position (14), and the other end of which is locatedadjacent to means for moving the demoulded component (24) and the emptymould (22), whereby a mould supporting member can be removed from themould before loading the latter, and the mould supporting member can bemoved by the further conveyor (16, 18) from said one end thereof to theother where the mould support member can be reunited with an empty mould(22).
 14. Apparatus according to claim 1, characterized in that theapparatus is adapted to strip a plurality of moulds (22) from respectivecomponents (24) simultaneously.
 15. A demoulding method comprising thesteps of supporting a flexible mould (22) with a moulded component (24)therein, and moving the mould (22) with component (24) in a linear pathto a location whereat the mould (22) is clamped at one edge thereof, andthen moving the mould (22) in a direction away from the supporting means(12), the component (24) continuing to move in the linear path, wherebyto strip the mould (22) from one edge of the component (24) to anopposed edge thereof, whereby to remove the mould (22) from thecomponent (24).
 16. A method according to claim 15, characterized by thestep of retaining the component (24) on the supporting means (12) whichthe mould (22) is stripped from the component.
 17. A method according toclaim 15, characterized in that the mould (22) is moved through an angleaway from the component (24).
 18. A method according to claim 14,characterized in that pressure is applied to the mould (22) with thecomponent (24) therein at a spaced location from said one edge of themould, whereby to retain the component (24) on the supporting means (12)while separation takes place.